1. Field of the Invention
The present invention relates to a bonding construction in which a rotary shaft made of a resin material is bonded to a lever for transmitting a torque to the rotary shaft.
2. Description of the Related Art
A conventional bonding construction for rotary members is disclosed, for example, in Japanese Patent Publication (Kokai) No. 794051, for an inhibitor switch that detects the "shift-position" in a transmission of an automobile. In the conventional construction, a rotary shaft is journaled in a housing, and an operating lever is coupled to the end portion of the rotary shaft. The shaft and lever are made of a synthetic resin material. The shaft and lever are bonded together by heat-fusion or ultrasonic welding.
However, with the conventional bonding construction, the rotary shaft and operating lever are bonded merely by heat fusion or ultrasonic welding. Thus, the bonded portion through which a large torque is transmitted may break and fail to perform its intended function if a sufficient adhesion is not provided. Providing a fusion area large enough for withstanding a large torque necessitates a large diameter of the rotary shaft, resulting in a large overall size of the construction. This is a disadvantage.